Step By step A bit of A blur
Create realistic soft backdrops by using a depth map in combination with the powerful lens blur filter
01 Select the Subject
Grab the Quick Selection tool and paint over the area you want to remain sharp (Alt-paint to subtract if it goes wrong). Click the ‘Refine Edge’ button. Paint along tricky edges like the hair to improve the selection. Once done, choose Output to: Layer Mask and hit OK.
02 Prepare a gradient
Duplicate the layer with Cmd/ctrl+j then Shift-click the layer mask thumbnail on the lower layer to disable it. Highlight the upper layer thumbnail and hit Cmd/ctrl+i to invert. Next, grab the Gradient tool and choose the ‘Foreground to Transparent’ preset in the tool options.
03 Follow the Fall-off
Hit D and X to set colour to black. Choose the ‘Linear Gradient’ style, then drag up from the bottom to add a gradient that runs through the scene in the direction that natural fall-off would occur. When we apply the filter, black areas will come out sharper, white softer.
04 add the blur
Double-click the image thumbnail on the top layer. Go to Filter>blur>lens Blur. Choose Source: Layer Mask, then increase Radius to create the blur. Zoom in close and compare the noise in the sharp area with the soft areas, use the Noise Amount slider to match it. Hit OK.
05 analyse the results
Shift-click the mask thumbnail to disable it. Check the results; some of the chairs should be slightly sharper, so we’ll run the filter again. Duplicate the bottom layer with Cmd/ctrl+j, drag the copy to the top of the stack and Alt-drag the mask thumbnail from the layer below.
06 tweak the depth map
Highlight the mask thumbnail. Grab the Brush tool, lower opacity to about 30%, then paint areas with black (sharper) or white (softer). Alt-click the mask thumbnail to toggle the mask view on or off. Highlight the image thumbnail and hit Cmd/ctrl+f to apply the blur again.